pthread cleanup API

ThreadCancellation_async/master_slave/master_slave.c

@@ -1,5 +1,20 @@
 #include "master_slave.h"
 
+void
+memory_cleanup_handler(void* arg) {
+	
+	printf("%s invoked ...\n", __FUNCTION__);
+	free(arg);
+}
+
+void
+file_cleanup_handler(void* arg) {
+	
+	printf("%s invoked ...\n", __FUNCTION__);
+	fclose((FILE*)arg);
+
+}
+
 void *
 write_into_file(void* arg) {
 	
@@ -14,15 +29,22 @@ write_into_file(void* arg) {
 	/* Mode of cancellation */
 	pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, 0);
 	int* thread_id = (int*)arg;
+
+	/* When pthread_cancel is invoked and this thread get the
+	signal to get cancelled, this API is invoked to free up the 
+	resources used by this thread.*/
+	pthread_cleanup_push(memory_cleanup_handler, arg);
 	
 	sprintf(file_name, "thread_%d.txt", *thread_id);
 
 	FILE* fptr = fopen(file_name, "w");
 
+	pthread_cleanup_push(file_cleanup_handler, fptr);
+
 	if (!fptr) {
 		printf("Error : Could not open log file %s, errno = %d\n",
 			file_name, errno);
-		return 0;
+		pthread_exit(0);
 	}
 
 	while (1) {
@@ -32,6 +54,16 @@ write_into_file(void* arg) {
 		sleep(1);
 	}
 
-	fclose(fptr);
+	/* If this thread is successfully executed and the cancellation request
+	is not invoked till now then, the stack where resource free API are
+	need to be cleaned.*/
+	pthread_cleanup_pop(0);
+	pthread_cleanup_pop(0);
+
+	/*This is not executed as this thread is in infinite loop
+	and when the pthread_cancel is executed this thread is cancelled
+	while it was executing in the loop. Hence, this causes resource
+	leakage.*/
+	// fclose(fptr);
 	return 0;
 }